| I have some experience with LiFePO4 cells as I have been using them for 2 years in my e-vanagon and saturn conversion. They are great for cars but I think they would be a poor choice for our electraks for these reasons. 1. cost( although with a cycle life of over 2000 cycles they cost less for the long haul as long as you don't destroy them) 2.lack of weight 3.If you don't use a BMS you have to be damn sure you don't overcharge or over discharge as you will damage cells and in the worst case possibly have a really hot fire in your garage at 2am. LiFePO4 is safer than other Li chemistries but things can still happen if you go where you're not supposed to go. 4.If you plan to use the tractor in the winter you really need to make sure the cells are above 32 degrees before you charge them or they will be damaged . Depending on where the electrak is stored you may need a way to heat the cells before starting a charge. For those of you interested in learning more about this battery chemistry , there is a pretty good white board talk by Jack Rickard on http://www.evtv.me/vidarch.html. He shows you what is inside a cell, basic cell chemistry, what happens when you go too far in either direction , and he talks about the cycle life of a cell. The white board talk starts about 35 min. into the video. Kimball |